基于三场演化规律的浅埋近距煤层减损开采研究

Damage-reducing mining based on three fields evolution in shallow buried closely spaced multi-seam

为探索基于三场(应力场、位移场和裂隙场)演化机理的浅埋近距煤层减损开采方法,实现陕北侏罗纪煤田的安全绿色开采,以柠条塔煤矿北翼东区1-2与2-2煤层开采为背景,结合物理模拟、理论分析和工程实践的方法,揭示了浅埋近距煤层开采的三场演化机理,分析了区段煤柱错距对集中应力、覆岩与地表移动及裂缝发育的影响,得到了基于三场耦合控制的合理煤柱错距。研究表明,下煤层煤柱的布置,应同时避开上煤层煤柱集中应力影响区和采空区中部压实区。合理的区段煤柱错距可以减缓重复采动后地表的不均匀沉降程度,同时,能够减轻地裂缝的发育。避开集中应力、减缓地表不均匀沉降、减轻地裂缝发育的合理煤柱错距存在耦合交集,得到柠条塔煤矿1-2与2-2煤层开采的煤柱错距为40~50 m,研究可为浅埋近距煤层减损开采提供新方法。

In order to explore the damage-reducing mining method based on three-field(stress field,displacement field,and fracture field)evolution in shallow buried closely spaced multi-seam,realize safe and green mining in Jurassic coalfield in northern Shaanxi,with No.1-2 and No.2-2 seams mining in Ningtiaota coalmine as the background,through physical simulation,theoretical analysis and engineering practice,the three-field evolution mechanism of shallow buried closely spaced multi-seam mining has been revealed,and the effect of coal pillar staggered distance on concentrated stress,subsidence and fractures development of overburden and surface has been analyzed.Meanwhile,the rational coal pillar staggered distance based on coupling control of three-field has been obtained.The results have shown that the arrangement of lower pillar should avoid the concentrated stress in the upper coal seam and the compacting area in the middle of upper goaf.Rational coal pillar staggered distance can decrease the uneven surface subsidence and the development of surface fractures after repetition mining,and it has coupling intersection.It is obtained that the rational coal pillar staggered distance of No.1-2 and No.2-2 seams is 40~50 m in Ningtiaota coalmine,and the research can provide innovative method for damage-reducing mining based on three field evolution in shallow buried closely spaced multi-seam.